Induction heating type cooktop with reduced thermal deformation of thin film

ABSTRACT

An induction heating type cooktop includes a cover plate that is coupled to a top of a case and that includes an upper plate configured to seat an object to be heated, a working coil disposed inside the case and configured to heat the object, an insulator disposed between a bottom surface of the upper plate and the working coil, and a thin film that is disposed on at least one of a top surface of the upper plate or the bottom surface of the upper plate and that includes a plurality of sub-films that are arranged about a central portion of the thin film. An outer boundary of one of the plurality of sub-films is positioned radially outward of an outer boundary of another of the plurality of sub-films relative to the central portion of the thin film.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/849,558, filed on Apr. 15, 2020, which claims the benefit of KoreanPatent Application No. 10-2019-0169894, filed on Dec. 18, 2019, thedisclosures of which are incorporated herein in their entirety byreference.

TECHNICAL FILED

The present disclosure relates to an induction heating type cooktopincluding a thin film and, more specifically, to reduction of thermaldeformation of a thin film in an induction heating type cooktop.

BACKGROUND

Various types of cookware are used to cook food at home or atrestaurants. For example, gas ranges may use gas as fuel to heat food.In some cases, cooking devices may heat a target heating object such asa pot and a cooking vessel using electricity rather than gas.

Methods for heating a target heating object using electricity may bedivided into a resistance heating method and an induction heatingmethod. In the electric resistance heating method, a target heatingobject may be heated by heat that is generated when a current flows in ametal resistance wire or a non-metallic heating element such as SiliconCarbide (SIC) and transferred to the target heating object (e.g., acooking vessel) through heat dissipation or heat transfer. In theinduction heating method, a target heating object may be heated by aneddy current generated in the target heating object made of a metalmaterial using an electrical field that is generated around a coil whena high frequency power having a predetermined magnitude is applied tothe coil.

The induction heating method may be applied to cooktops.

In some cases, a cooktop using an induction heating method may only heatan object made of a magnetic material. That is, when an object made of anonmagnetic material (for example, heat-resistant glass, porcelain,etc.) is disposed on the cooktop, the cooktop may not heat thenonmagnetic material object.

In some cases, an induction heating device may include a heating platedisposed between a cooktop and a nonmagnetic object to heat the object.Referring to Japanese Patent Application Laid-Open Publication No.5630495 (Oct. 17, 2014), a method of implementing induction heating byadding a heating plate is disclosed. However, the aforementioned methodhas problems that heating efficiency of the heating plate may be low,and a cooking time required to heat ingredients contained in the targetheating object may be increased.

In some cases, a hybrid cooktop may heat a nonmagnetic object through aradiant heater using an electric resistance heating method, where amagnetic object is heated through a working coil by induction. In somecases, an induction heating method is applied. Referring to JapanesePatent Application Laid-Open Publication No. 2008-311058 (Dec. 25,2008), a configuration of the hybrid cooktop is disclosed. However, theaforementioned method has problems that output of the radiant heater maybe low, and a heating efficiency may be low. A user may feelinconvenience in considering a material of a target heating object whenplacing the target heating object in the heating area.

In some cases, an all metal cooktop may heat a metal object (e.g., anonmagnetic metal and a magnetic object. Referring to U.S. Pat. No.6,770,857 (Aug. 3, 2004), a configuration of the all metal cooktop isdisclosed.

However, the aforementioned method has a problem that a non-magnetic maynot heat a nonmagnetic and non-metallic object. In addition, a heatingefficiency may be lower than a radiant heater technology, and a materialcost may be high.

SUMMARY

The present disclosure describes an induction heating type cooktopcapable of heating both a magnetic object and a nonmagnetic object.

The present disclosure also describes implementations to prevent damageto a thin film (or thin layer, hereinafter referred as thin film) andother components included as a heating target in an induction heatingtype cooktop that is capable of heating both a magnetic object and anonmagnetic object.

The present disclosure also describes an induction heating type cooktophaving a thin film disposed in various ways so as to prevent damage orthermal deformation of the thin film. The thin film may be inductivelyheated when a working coil is operated to inductively heat a magneticobject or a nonmagnetic object placed on an upper plate of the cooktop.

Objects of the present disclosure are not limited thereto, and otherobjects and advantages of the present disclosure will be understood bythe following description, and will become more apparent fromimplementations of the present disclosure. Furthermore, the objects,features and advantages of the present disclosure can be realized bymeans disclosed in the accompanying claims or combination thereof.

According to one aspect of the subject matter described in thisapplication, an induction heating type cooktop includes a cover platethat is coupled to a top of a case and that includes an upper plateconfigured to seat an object to be heated, a working coil disposedinside the case and configured to heat the object, an insulator disposedbetween a bottom surface of the upper plate and the working coil, and athin film that is disposed on at least one of a top surface of the upperplate or the bottom surface of the upper plate and that includes aplurality of sub-films that are arranged about a central portion of thethin film. An outer boundary of one of the plurality of sub-films ispositioned on a radially different position from an outer boundary ofanother of the plurality of sub-films relative to the central portion ofthe thin film.

Implementations according to this aspect may include one or more of thefollowing features. For example, the thin film may be coated on the atleast one of the top surface of the upper plate or the bottom surface ofthe upper plate. In some examples, the thin film may be configured to,based on the object being placed on the top surface of the upper plate,form an equivalent circuit including a resistance component and aninductor component. In some examples, the working coil may be configuredto, based on a magnetic object being placed on the top surface of theupper plate, apply an induced current to the magnetic object and theplurality of sub-films.

In some implementations, at least one of the plurality of sub-films mayhave a ring shape. In some examples, the plurality of sub-films mayinclude a sub-film that is disposed at a center of the plurality ofsub-films and that defines a hole in the central portion of the thinfilm. In some examples, the plurality of sub-films include a sub-filmthat is disposed at a center of the plurality of sub-films and thatcovers the central portion of the thin film.

In some implementations, a width of each of the plurality of sub-filmsis included in a predetermined range. In some examples, each of theplurality of sub-films may have a uniform width. In some examples,widths of the plurality of sub-films are different each other. In someexamples, each of the plurality of sub-films has a non-uniform widthwhich is included in a predetermined range.

In some implementations, the plurality of sub-films may be spaced apartfrom one another to thereby define a gap having one or more distancesbetween two of the plurality of sub-films, which in included in apredetermined range. In some implementations, at least one of theplurality of sub-films may be made of a conductive material having amagnetic property. In some implementations, at least one of theplurality of sub-films is made of a conductive material having anonmagnetic property.

In some implementations, each of the plurality of sub-films may have athickness in a range from 0.5 μm to 1,000 μm, and the plurality ofsub-films may be configured to, based on the object being placed on theupper plate, form an equivalent circuit including a resistance componentand an inductor component to thereby be inductively heated by theworking coil.

In some implementations, the plurality of sub-films may be configuredto, based on a magnetic object being placed on the top surface of theupper plate, form, together with the magnet object, an equivalentcircuit including a resistance component and an inductor component.

In some implementations, the thin film may include a plurality of layersthat are made of different materials and that are disposed on the atleast one of the top surface or the bottom surface of the upper plate.In some examples, at least one of the plurality of layers may beconfigured to, based on a nonmagnetic object being placed on the topsurface of the upper plate, form an equivalent circuit including aresistance component and an inductor component to thereby be inductivelyheated. In some examples, at least one of the plurality of layers may beconfigured to form, together with the object, an equivalent circuitincluding a resistance component and an inductor component to therebyinductively heat the object that is made of aluminum.

In some implementations, a thickness of the thin film may be less than askin depth of the thin film.

In some implementations, induction heating of a magnetic object and anonmagnetic object may be performed using an induction heating deviceincluding a plurality of sub-films rather than a single thin film. Insome cases, an attached thin film may be deformed by a difference intemperature at a portion which is repeatedly heated and cooled. In orderto prevent or reduce such thermal deformation, the thin film to beinductively heated may include a plurality of sub-films to reduce thedifference in temperature at the portion to be inductively heated in onethin film.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainimplementations will be more apparent from the following detaileddescription taken in conjunction with the accompanying drawings.

FIG. 1 is a diagram illustrating an example of an induction heating typecooktop in related art.

FIG. 2 is a diagram illustrating an example of an induction heating typecooktop according to the present application.

FIG. 3 is a diagram illustrating example elements disposed in an examplecase of the induction heating type cooktop shown in FIG. 2 .

FIGS. 4 and 5 are diagrams illustrating examples of a thickness of athin film and a skin depth of the thin film of an induction heating typecooktop.

FIGS. 6 and 7 are diagrams illustrating examples of an electricimpedance between a thin film and a target heating object depending on atype of the target heating object.

FIG. 8 is a diagram illustrating an example of an induction heating typecooktop.

FIG. 9 is a diagram illustrating example elements disposed in an examplecase of the induction heating type cooktop shown in FIG. 8 .

FIG. 10 is a diagram illustrating an example of a target heating objectpositioned on the induction heating type cooktop shown in FIG. 8 .

FIG. 11 is a diagram illustrating example elements disposed in anexample case of an induction heating type cooktop having a thin film.

FIG. 12 is a diagram illustrating example elements disposed in anexample case of an induction heating type cooktop having a thin film.

FIG. 13 is a diagram illustrating example elements disposed in anexample case of an induction heating type cooktop having a thin film TL.

FIG. 14 illustrates an example of an equivalent circuit that includes aresistance component and an inductor component and that is definedthrough a thin film included in an induction heating type cooktop and atarget heating object.

FIG. 15 illustrates an example of a thin film including a plurality ofsub-films.

FIG. 16A illustrates an example of a thin film that includes a pluralityof sub-films that are disposed on a top and a bottom of an upper plateof an induction heating type cooktop.

FIG. 16B is a plan view illustrating an example of the thin filmincluding the plurality of sub-films in FIG. 16A.

FIG. 17A illustrates an example a thin film including a plurality ofsub-films that are disposed on a top and a bottom of an upper plate ofan induction heating type cooktop.

FIG. 17B is a plan view illustrating the thin film including theplurality of sub-films in FIG. 17A.

FIG. 18 illustrates examples of various types of a plurality ofsub-films of a thin film of an induction heating type cooktop andexample widths of the plurality of sub-films.

FIG. 19 illustrates examples of various types of a plurality ofsub-films of a thin film of an induction heating type cooktop andexample gaps between the plurality of sub-films.

FIG. 20 illustrates an example of heat distribution across a thin filmincluding a plurality of sub-films that are inductively heated.

DETAILED DESCRIPTION

Hereinafter, implementations of the present disclosure will be describedin detail with reference to the drawings so that those skilled in theart to which the present disclosure pertains can easily perform thepresent disclosure. The present disclosure may be implemented in manydifferent forms and is not limited to the implementations describedherein.

In order to illustrate this application, a part that is not related tothe description may be omitted, and the same or similar components aredenoted by the same reference numerals throughout the specification.Further, some implementations of this application will be described indetail with reference to exemplary drawings. In adding the referencenumerals to the components of each drawing, the same components may havethe same sign as possible even if they are displayed on differentdrawings. Further, in describing this application, when it is determinedthat a detailed description of a related known configuration and afunction may obscure the gist of this application, the detaileddescription thereof will be omitted.

Further, in implementing the present disclosure, for convenience ofexplanation, components may be described by being subdivided; however,these components may be implemented in a device or a module, or a singlecomponent may be implemented by being divided into a plurality ofdevices or modules.

FIG. 1 illustrates an induction heating type cooktop in related art.

For example, the induction heating type cooktop 1 may include workingcoils WC1 and WC2 to heat an object made of a material capable of beinginductively heated is heated. For example, the working coils WC1 and WC2may be operated to inductively heat a magnetic material disposed on anupper plate 15. In some cases, where thin films CTL1 and CTL2 arecapable of being inductively heated, a nonmagnetic object disposed onthe upper plate 15 may be indirectly heated. That is, the thin filmsCTL1 and CTL2 may be made of a predetermined material capable of beinginductively heated. Accordingly, the thin films CTL1 and CTL2 may beinductively heated in the course of induction heating of a targetheating object disposed on the upper plate 15. Here, the target heatingobject to be indirectly heated through the inductively heated thin filmsCTL1 and CTL2 may be heated faster as the areas of the thin films CTL1and CTL2 are wider and thicker. The area for heating the target heatingobject may correspond to the entire area in which a physicalconfiguration constituting the thin films CTL1 and CTL2 faces the targetheating object.

The thin films CTL1 and CTL2 to be inductively heated may have a heatdistribution of a portion to be heated according to a shape thereof. Forexample, when the thin films CTL1 and CTL2 have a ring shape forming aloop, the heat distribution of the thin films CTL1 and CTL2 may changealong a circumferential direction (CD) and a radial direction (RD) ofthe loop. In particular, the inductively heated ring-shaped thin filmsCTL1 and CTL2 have the highest temperature portion to the lowesttemperature portion within a predetermined radius range, and thetemperature difference between the thin films CTL1 and CTL2 may lead tothermal deformation with respect to the shape of a single componentincluded in the thin films CTL1 and CTL2.

In some cases, the thin films CTL1 and CTL2 each may include a widesingle film to heat the entire bottom surface of a target heating objectand to quickly heat the target heating object. In some cases, where thethin films CTL1 and CTL2 include a single film are inductively heated,although the single film is heated as a whole, the central portion ofthe single film may be heated to the highest temperature in the radialdirection, and the single film may be heated to the lowest temperaturetoward the outer or inner boundary. Referring to FIG. 1 , the thin filmsCTL1 and CTL2 may each include a ring-shaped single film. A centralportion Sp2 of the single film may be inductively heated to the highesttemperature, and a remaining portion Sp3 adjacent to the inner boundaryor a remaining portion Sp1 adjacent to the outer boundary may be heatedto a relatively low temperature. Such temperature distribution in eachof the inductively heated thin films CTL1 and CTL2 is resulted becausethe intensity distribution of each of the magnetic fields generated bythe working coils WC1 and WC2 is not uniform. Since the non-uniformmagnetic field of each of the working coils WC1 and WC2 passes through asingle film, the heat generated inside each of the large-area thin filmsCTL1 and CTL2 is also not uniform on each surface. The temperaturedifference in each of these components leads to thermal deformation,which makes the thin films CTL1 and CTL2 relatively inferior indurability.

Hereinafter, various implementations of an induction heating typecooktop for preventing thermal deformation will be described accordingto the present application.

FIG. 2 is a diagram illustrating an example of an induction heating typecooktop.

Referring to FIG. 2 , an induction heating type cooktop 10 may include acase 25, a cover plate 20, working coils WC1 and WC2 (that is, first andsecond working coils), and thin films TL1 and TL2 (that is, first andsecond thin films).

The working coils WC1 and WC2 may be installed in the case 25.

In some implementations, a variety of devices related to driving of aworking coil other than the working coils WC1 and WC2 may be installedin the case 25. For example, the devices relating to driving of aworking coil may include a power part for providing alternating currentpower, a rectifying part for rectifying alternating current power fromthe power part to direct current power, an inverter part for invertingthe direct power rectified by the rectifying part to a resonance currentthrough a switching operation, a control part for controlling operationsof various devices in the induction heating type cooktop 10, a relay ora semi-conductor switch for turning on and off a working coil, and thelike. Regarding this, a detailed description will be herein omitted.

The cover plate 20 may be coupled to a top of the case 25, and mayinclude an upper plate 15 for placing a target object to be heated onthe top.

For example, the cover plate 20 may include the upper plate 15 forplacing a target object to be heated, such as a cooking vessel.

In some examples, the upper plate 15 may be made of a glass material(e.g., ceramic glass).

In some implementations, an input interface may be provided in the upperplate 15 to receive an input from a user and transfer the input to acontrol part that serves as an input interface. The input interface maybe provided at a position other than the upper plate 15.

The input interface may be configured to allow a user to input a desiredheat intensity or an operation time of the induction heating typecooktop 10. The input interface may be implemented in various forms,such as a mechanical button or a touch panel. The input interface mayinclude, for example, a power button, a lock button, a power controlbutton (+, −), a timer control button (+, −), a charging mode button,and the like. The input interface may transfer an input provided by auser to a control part for the input interface, and the control part forthe input interface may transfer the input to the aforementioned controlpart (that is, a control part for an inverter). The aforementionedcontrol part may control operations of various devices (e.g., a workingcoil) based on an input (that is, a user input) provided from thecontrol part for the input interface, and a detailed description thereofwill be omitted. In some examples, the control part may be a controller,a processor, or an electric circuit.

The upper plate 15 may visually display whether the working coils WC1and WC2 are being driven or not and intensity of heating (that is,thermal power). For example, a fire hole shape may be displayed in theupper plate 15 by an indicator that includes a plurality of lightemitting devices (e.g., light emitting diodes (LEDs)) provided in thecase 25.

The working coils WC1 and WC2 may be installed inside the case 25 toheat a target heating object.

Specifically, driving of the working coils WC1 and WC2 may be controlledby the aforementioned control part. When the target heating object ispositioned on the upper plate 15, the working coils WC1 and WC2 may bedriven by the control part.

In some implementations, the working coils WC1 and WC2 may directly heata magnetic target heating object (that is, a magnetic object) and mayindirectly heat a nonmagnetic target heating object (that is, anonmagnetic object) through the thin films TL1 and TL2 which will bedescribed in the following.

The working coils WC1 and WC2 may heat a target heating object byemploying an induction heating method and may be provided to overlap thethin films TL1 and TL2 in a longitudinal direction (that is, a verticaldirection or an up-down direction).

Although FIG. 2 illustrates that two working coils WC1 and WC2 areinstalled in the case 25, but aspects of the present disclosure are notlimited thereto. That is, one working coil or three or more workingcoils may be installed in the case 25. Yet, for convenience ofexplanation, an example in which two working coils WC1 and WC2 areinstalled in the case 25 will be described.

The thin films TL1 and TL2 may be coated on the upper plate 15 to heat anonmagnetic object among target heating objects.

Specifically, the thin films TL1 and TL2 may be coated on at least oneof a top surface and a bottom surface of the upper plate 15 and may beprovided to overlap the working coils WC1 and WC2 in a longitudinaldirection (that is, a vertical direction or an up-down direction).Accordingly, it may be possible to heat the corresponding target heatingobject, regardless of a position and a type of the target heatingobject.

The thin films TL1 and TL2 may have at least one of a magnetic propertyand a nonmagnetic property (that is, either or both of the magneticproperty and the nonmagnetic property).

The thin films TL1 and TL2 may be, for example, made of a conductivematerial (e.g., aluminum). As illustrated in the drawing, the thin filmsTL1 and TL2 may be coated on a top surface of the upper plate 15 bytaking the form of a plurality of rings having different diameters.However, aspects of the present disclosure are not limited thereto.

That is, the thin films TL1 and TL2 may include a material other than aconductive material and may be coated on the upper plate 15 by taking adifferent form. Hereinafter, for convenience of explanation, an examplein which the thin films TL1 and TL2 is made of a conductive material andcoated on the upper plate 15 in the form of a plurality of rings havingdifferent diameters will be described.

FIG. 2 shows the two thin films TL1 and TL2, but the number of thinfilms included in the cooktop 10 is not limited thereto. That is, thecooktop 10 may include at least one thin film as a thin filmcorresponding to each working coil.

However, FIG. 2 is a diagram illustrating an exemplary dispositionalrelationship between elements used in the present disclosure. Therefore,shapes, numbers, and positions of the elements should not be construedas being limited to the example shown in FIG. 2 .

The thin films TL1 and TL2 will be described later with reference toFIG. 11 and following drawings.

FIG. 3 is a diagram illustrating example elements provided inside a caseof the induction heating type cooktop shown in FIG. 2 .

Referring to FIG. 3 , the induction heating type cooktop 10 may furtherinclude an insulator 35, a shield plate 45, a support member 50, and acooling fan 55.

Since elements disposed in the surroundings of a first working coil WC1are identical to elements disposed in the surroundings of a secondworking coil WC2 (the working coil in FIG. 2 ), the elements (e.g., thefirst thin film TL1, the insulator 35, the shield plate 45, the supportmember 50, and the cooling fan 55) in the surroundings of the firstworking coil WC1 will be hereinafter described for convenience ofexplanation.

The insulator 35 may be provided between a bottom surface of the upperplate 15 and the first working coil WC1.

Specifically, the insulator 35 may be mounted to the cover plate 20,that is, the bottom of the upper plate 15. The first working coil WC1may be disposed below the insulator 35.

The insulator 35 may block heat, which is generated when the first thinfilm TL1 or a target heating object HO is heated upon driving of thefirst working coil WC1, from being transferred to the first working coilWC1.

That is, when the first thin film TL1 or the target heating object HO isheated by electromagnetic induction of the first working coil WC1, heatof the first thin film TL1 or the target heating object HO may betransferred to the upper plate 15 and the heat transferred to the upperplate 15 may be transferred to the first working coil WC1, therebypossibly causing damage to the first working coil WC1.

By blocking the heat from being transferred to the first working coilWC1, the insulator 35 may prevent damage of the first working coil WC1caused by the heat and furthermore prevent degradation of heatingperformance of the first working coil WC1.

A spacer, which is not an essential constituent element, may beinstalled between the first working coil WC1 and the insulator 35.

Specifically, the spacer may be inserted between the first working coilWC1 and the insulator 35, so that the first working coil WC1 and theinsulator 35 do not directly contact each other. Accordingly, the spacermay block heat, which is generated when the first thin film TL1 and thetarget heating object HO are heated upon driving of the first workingcoil WC1, from being transferred to the first working coil WC1 throughthe insulator 35.

That is, since the spacer may share the role of the insulator 35, it maybe possible to minimize a thickness of the insulator 35 and accordinglyminimize a gap between the target heating object HO and the firstworking coil WC1.

In addition, a plurality of spacers may be provided, and the pluralityof spaces may be disposed to be spaced apart from each other in the gapbetween the first working coil WC1 and the insulator 35. Accordingly,air suctioned into the case 25 by the cooling fan 55 may be guided tothe first working coil WC1 by the spacer.

That is, the spacer may guide air, introduced into the case 25 by thecooling fan 55, to be properly transferred to the first working coilWC1, thereby improving cooling efficiency of the first working coil WC1.

The shield plate 45 may be mounted to a bottom of the first working coilWC1 to block a magnetic field occurring downwardly upon driving of thefirst working coil WC1.

Specifically, the shield plate 45 may block the magnetic field occurringdownwardly upon driving of the first working coil WC1 and may besupported upwardly by the support member 50.

The support member 50 may be installed between a bottom surface of theshield plate 45 and a bottom surface of the case 25 to support theshield plate 45 upwardly.

Specifically, by supporting the shield plate 45 upwardly, the supportmember 50 may indirectly support the insulator 35 and the first workingcoil WC1 upwardly. In doing so, the insulator 35 may be brought intotight contact with the upper plate 15.

As a result, it may be possible to maintain a constant gap between thefirst working coil WC1 and the target heating object HO.

The support member 50 may include, for example, an elastic object (e.g.,a spring) to support the shield plate 45 upwardly, but aspects of thepresent disclosure are not limited thereto. In addition, the supportmember 50 is not an essential element and thus it may be omitted fromthe induction heating type cooktop 10.

The cooling fan 55 may be installed inside the case 25 to cool the firstworking coil WC1.

Specifically, driving of the cooling fan 55 may be controlled by theaforementioned control part and the cooling fan 55 may be installed at aside wall of the case 25. The cooling fan 55 may be installed at aposition other than the side wall of the case 25. In an implementation,for convenience of explanation, an example in which the cooling fan 55is installed at the side wall of the case 25 will be described.

The cooling fan 55 may suction outdoor air from the outside of the case25, as shown in FIG. 3 , and transfer the suctioned air to the firstworking coil WC1. The cooling fan 55 may suction indoor air (e.g.,heated air) of the case 25 and discharge the suctioned air to theoutside of the case 25.

In doing so, it may be possible to efficiently cool internal elements(e.g., first working coil WC1) of the case 25.

In some examples, the outdoor air transferred from the outside of thecase 25 to the first working coil WC1 by the cooling fan may be guidedto the first working coil WC1 by the spacer. Accordingly, it may bepossible to directly and efficiently cool the first working coil WC1,thereby improving endurance of the first working coil WC1. That is, itmay be possible to improve the endurance by preventing thermal damage.

In some examples, the induction heating type cooktop 10 may include oneor more of the above-described features and configurations. Hereinafter,features and configurations of the aforementioned thin film will bedescribed in more detail with reference to FIGS. 4 to 7 .

FIGS. 4 and 5 are diagrams illustrating a relation between a thicknessand a skin depth of a thin film. FIGS. 6 and 7 are diagrams illustratinga variation of impedance between a thin film and a target heating objectdepending on a type of the target heating object.

The first thin film TL1 and the second thin film TL2 have the sametechnical features, and the thin film TL1 and TL2 may be coated on thetop surface or the bottom surface of the upper plate 15. Hereinafter,for convenience of explanation, the first thin film TL1 coated on thetop surface of the upper plate 15 will be described as an example.

The first thin film TL1 has the following features.

In some implementations, the first thin film TL1 may include a materialhaving a low relative permeability.

For example, since the first thin film TL1 has a low relativepermeability, the skin depth of the first thin film TL1 may be deep. Theskin depth may refer to a depth by which a current can penetrate amaterial surface, and the relative permeability may be disproportionalto the skin depth. Accordingly, the lower the relative permeability ofthe first thin film TL1, the deeper the skin depth of the first thinfilm TL1.

In some examples, the skin depth of the first thin film TL1 may have avalue greater than a value corresponding to a thickness of the firstthin film TL1. That is, since the first thin film TL1 has a thinthickness (e.g., a thickness of 0.1 μm˜1,000 μm) and a skin depth of thefirst thin film TL1 is greater than the thickness of the first thin filmTL1, a magnetic field occurring by the first working coil WC1 may passthrough the first thin film TL1 and be then transferred to the targetheating object HO. As a result, an eddy current may be induced to thetarget heating object HO.

That is, as illustrated in FIG. 4 , when the skin depth of the firstthin film TL1 is narrower than the thickness of the first thin film TL1,it is difficult for the magnetic field occurring by the first workingcoil WC1 to reach the target heating object HO.

In some implementations, as illustrated in FIG. 5 , when the skin depthof the first skin depth TL1 is deeper than the thickness of the firstthin film TL1, most of the magnetic field generated by the first workingcoil WC1 may be transferred to the target heating object HO. That is,since the skin depth of the first thin film TL1 is deeper than thethickness of the first thin film TL1, the magnetic field generated bythe first working coil WC1 may pass through the first thin film TL1 andmost of the magnetic field energy may be dissipated in the targetheating object HO. In doing so, the target heating object HO may beheated primarily.

Since the first thin film TL1 has a thin thickness as described above,the thin film TL1 may have a resistance value that allows the first thinfilm TL1 to be heated by the first working coil WC1.

Specifically, the thickness of the first thin film TL1 may bedisproportional to the resistance value of the first thin film TL1 (thatis, a sheet resistance value). That is, the thinner the thickness of thefirst thin film TL1 coated on the upper plate 15, the greater theresistance value (that is, the sheet resistance) of the first thin filmTL1. As thinly coated on the upper plate 15, the first thin film TL1 maychange in property to a load resistance at which heating may bepossible.

The first thin film TL1 may have a thickness of, for example, 0.1 μm to1,000 μm, but not limited thereto.

The first thin film TL1 having the above-described characteristic ispresent to heat a nonmagnetic object, and thus, an impedance propertybetween the first thin film TL1 and the target heating object HO mayvary according to whether the target heating object HO positioned on thetop of the upper plate 15 is a magnetic object or a nonmagnetic object.

One or more examples, where the target heating object is a magneticobject, will be described in the following.

Referring to FIGS. 3 and 6 , when the first working coil WC1 is drivenwhile a magnetic target heating object HO is positioned on the top ofthe upper plate 15, a resistance component R1 and an inductor componentL1 of the magnetic target heating object HO may form an equivalentcircuit to that of a resistance component R2 and an inductor componentL2 of the first thin film TL1.

In this case, in the equivalent circuit, an impedance (that is, animpedance of R1 and L1) of the magnetic target heating object HO may besmaller than an impedance (that is, an impedance of R2 and L2) of thefirst thin film TL1.

Accordingly, when the aforementioned equivalent circuit is formed, themagnitude of an eddy current I1 applied to the magnetic target heatingobject HO may be greater than the magnitude of an eddy current I2applied to the first thin film TL1. More specifically, most of eddycurrents may be applied to the target heating object HO, thereby heatingthe target heating object HO.

That is, when the target heating object HO is a magnetic object, theaforementioned equivalent circuit may be formed and most of eddycurrents may be applied to the target heating object HO. Accordingly,the first working coil WC1 may directly heat the target heating objectHO.

Since some of eddy currents is applied even to the first thin film TL1,the first thin film TL1 may be heated slightly. Accordingly, the targetheating object HO may be indirectly heated to a certain degree by thethin film TL1. However, a degree to which the target heating object HOis heated indirectly by the first thin film TL1 may not be consideredsignificant, as compared with a degree to which the target heatingobject HO is heated directly by the first working coil WC1.

One or more examples, where a target heating object is a nonmagneticobject, will be described in the following.

Referring to FIGS. 3 and 7 , when the working coil WC1 is driven while anonmagnetic target heating object HO is positioned on the top of theupper plate 15, an impedance may not exist in the nonmagnetic targetheating object HO but exists in the first thin film TL1. That is, aresistance component R and an inductor component L may exist only in thefirst thin film TL1.

Accordingly, an eddy current I may be applied only to the first thinfilm TL1 and may not be applied to the nonmagnetic target heating objectHO. More specifically, the eddy current I may be applied only to thefirst thin film TL1, thereby heating the first thin film TL1.

That is, when the target heating object HO is a nonmagnetic object, theeddy current I may be applied to the first thin film TL1, therebyheating the first thin film TL1. Accordingly, the nonmagnetic targetheating object HO may be indirectly heated by the first thin film TL1that is heated by the first working coil WC1.

To put it briefly, regardless of whether the target heating object HO isa magnetic object or a nonmagnetic object, the target heating object HOmay be heated directly or indirectly by a single heating source which isthe first working coil WC1. That is, when the target heating object HOis a magnetic object, the first working coil WC1 may directly heat thetarget heating object HO, and, when the target heating object HO is anonmagnetic object, the first thin film TL1 heated by the first workingcoil WC1 may indirectly heat the target heating object HO.

As described above, the induction heating type cooktop 10 may be capableof heating both a magnetic object and a nonmagnetic object. Thus, theinduction heating type cooktop 10 may be capable of heating a targetheating object regardless of a position and a type of the target heatingobject. Accordingly, without determining whether the target heatingobject is a magnetic object or a nonmagnetic object, a user is allowedto place the target heating object in any heating region on the topplate, and therefore, convenience of use may improve.

In addition, the induction heating type cooktop 10 may directly orindirectly heat a target heating object using the same heating source,and therefore, a heat plate or a radiant heater is not necessary.Accordingly, it may be possible to increase heating efficiency and cutdown a material cost.

Hereinafter, an induction heating type cooktop will be described.

FIG. 8 is a diagram illustrating an example of an induction heating typecooktop. FIG. 9 is a diagram illustrating example elements providedinside a case of the induction heating type cooktop shown in FIG. 8 .FIG. 10 is a diagram illustrating an example of a target heating objectpositioned at the induction heating type cooktop shown in FIG. 8 .

An induction heating type cooktop 2 is identical to the inductionheating type cooktop 10 shown in FIG. 2 , except for some elements andeffects. Hence, a difference compared to the induction heating typecooktop 10 will be focused and described.

Referring to FIGS. 8 and 9 , the induction heating type cooktop 2 may bea zone-free cooktop.

Specifically, the induction heating type cooktop 2 may include a case25, a cover plate 20, a plurality of thin films TLGs, an insulator 35, aplurality of working coils WCGs, a shield plate 45, a support member 50,a cooling fan, a spacer and a control part.

Here, the plurality of thin films TLGs and the plurality of WCGs mayoverlap in a traverse direction and may be disposed to correspond toeach other in a one-to-one relationship. The plurality of thin filmsTLGs and the plurality of thin films WCGs may be in a many-to-manyrelationship rather than the one-to-one relationship. In someimplementations, for example, the plurality of thin films TLGs and theplurality of working coils WCGs may be arranged in a one-to-onerelationship.

For instance, the induction heating type cooktop 2 may be a zone-freecooktop including the plurality of thin films TLGs and the plurality ofworking coils WCGs, and therefore, it may be possible to heat a singletarget heating object HO by using some or all of the plurality ofworking coils WCGs at the same time or by using some or all of theplurality of thin films TLGs at the same time. In some examples, it maybe possible to heat the target heating object HO by using both some orall of the plurality of working coils WCG and some or all of theplurality of thin films TLGs.

Accordingly, as shown in FIG. 10 , in a region where the plurality ofworking coils WCG (see FIG. 9 ) and the plurality of thin films TLG arepresent (e.g., a region of the upper plate 15), it may be possible toheat target heating objects HO1 and HO2, regardless of sizes, positions,and types of the target heating objects HO1 and HO2.

FIG. 11 is a diagram illustrating example elements provided in a case ofan induction heating type cooktop 1000 having a thin film TL.

In some implementations, the induction heating type cooktop 1000described in FIG. 11 and other following drawings may correspond to theinduction heating type cooktop 10 used in various implementationsdescribed with reference to FIGS. 2 to 10 . Hence, elements of theinduction heating type cooktop 1000 not illustrated in FIG. 11 and otherfollowing drawings may be understood as selectively including elementsof the cooktop 10 within the scope supported by the descriptions ofFIGS. 2 to 10 .

In some implementations, the induction heating type cooktop 1000 mayinclude a cover plate 1020 coupled to the top of a case 1025 and havingan upper plate 1015 allowing a target heating object HO to be placed ona top thereof, a working coil WC provided inside the case 1025 to heatthe target heating object HO, a thin film TL disposed on at least one ofa top and a bottom of the upper plate 1015, and an insulator 1035provided between a bottom surface of the upper plate 1015 and theworking coil WC., the thin film TL may include a plurality of sub-filmseach having a different distance from a central portion to an outermostboundary.

In some implementations, a gap for preventing heat transfer from theinductively heated thin film TL may exist as a buffer between theworking coil WC and the thin film TL disposed on at least one of a topand a bottom of an upper plate 1015.

Referring to FIG. 11 , the cooktop 1000 may include a thin film TLincluding a plurality of sub-films on the top of the upper plate 1015.,the thin film TL disposed on the top of the upper plate 1015 may becoated on the top surface of the upper plate 1015. The thin film TLcoated on the top surface of the upper plate 1015 may be coated byvarious methods such as vacuum deposition (e.g., physical vapordeposition (PVD), etc.).

In some implementations, the thin film TL may be made of a material(e.g., silver (Ag), copper (Cu), nickel (Ni), STS, etc.) capable ofbeing inductively heated by the working coil WC, and may be determinedto be arranged with an optimal thickness.

In some implementations, the thin film TL may be an inductively heatedmaterial. For example, when the object to be heated HO is made ofaluminum, the thin film TL may include a layer made of a materialcapable of being inductively heated together with a target heatingobject. That is, the target heating object HO made of aluminum and thethin film TL including the plurality of sub-films may form an equivalentcircuit including a resistance component and an inductor component, andthe resistance component and the inductor component constituting theequivalent circuit may be included at least in part within apredetermined range of components capable of being inductively heated bythe working coil WC.

In some implementations, the thin film TL may be in contact with theupper surface of the upper plate 1015 through an adhesive layer foradhesion to the upper plate 1015 made of a glass material or the like.For example, the adhesive layer may be made of a material suitable foradhesion between different materials (e.g., glass and metal)., theadhesive layer may be pretreated by plasma, etching, or the like., thethin film TL may be protected by a protective layer applied after beingcoated on the top surface of the upper plate 1015.

In some implementations, the overall shape of the thin film TL maycorrespond to the shape of the working coil WC for inductively heatingthe thin film TL. For example, when the working coil WC has a circularring shape, the plurality of sub-films constituting the thin film TL mayhave a circular ring shape corresponding to the working coil WC.However, the shape of the thin film TL is not necessarily limited to theshape of the working coil WC. Therefore, only some of the plurality ofsub-films may correspond to the shape of the working coil WC or may notcorrespond to the shape of the working coil WC

FIG. 12 is a diagram illustrating elements provided in a case of aninduction heating type cooktop having a thin film.

In some examples, the cooktop 1000 may be a thin film TL including aplurality of sub-films on the bottom of the upper plate 1015. In someimplementations, the thin film TL disposed on the bottom of the upperplate 1015 may be coated on the bottom surface of the upper plate 1015,and the coating method may be any of various methods including vacuumdeposition as described in FIG. 11 . In addition to a layer including amaterial to be inductively heated, at least one additional layer to bedisposed on the bottom of the upper plate 1015 may be further included.

FIG. 13 is a diagram illustrating example elements provided in a case ofan induction heating type cooktop having a thin film TL.

In some implementations, the cooktop 1000 may include thin films TL1 andTL2 including a plurality of sub-films on the top and the bottom of theupper plate 1015. In the aforementioned implementations related to FIGS.2 and 4 , the first and second thin films TL1 and TL2 may be inductivelyheated by the working coils WC1 and WC2, respectively. In the presentimplementation, the thin films TL1 and TL2 may be inductively heated byone working coil WC. For this purpose, the thin films TL1 and TL2 may bearranged in a vertical direction. In some implementations, the thinfilms TL1 and TL2 disposed on the top and the bottom of the upper plate1015 may be coated on the bottom surface of the upper plate 1015, andthe coating method may be any of various methods including vacuumdeposition, as described with reference to FIGS. 11 and 12 . In additionto a layer made of a material to be inductively heated, at least oneadditional layer (an adhesive layer or a protective layer) may befurther included and disposed on the top and bottom of the upper plate1015.

In some implementations, the thin films TL1 and TL2 disposed on the topand the bottom of the upper plate 1015 may be disposed on the upperplate 1015 in the same structure; the structures of the thin films TL1and TL2 disposed on the top and the bottom of the upper plate 1015 maybe different from each other. For example, the thin film TL1 disposed onthe top of the upper plate 1015 may be protected by a protective layer,and the thin film TL2 disposed on the bottom of the upper plate 1015 maynot be protected by the protective layer or by a layer different fromthe protective layer of the thin film TL disposed on the top of theupper plate 1015.

In some implementations, the plurality of sub-films constituting thethin films TL1 and TL2 disposed on the top and the bottom of the upperplate 1015 may have different shapes on the top and the bottom of theupper plate 1015. Referring to FIG. 13 , the number of sub-filmsconstituting the thin film TL1 disposed on the top of the upper plate1015 may be different from the number of sub-films constituting the thinfilm TL2 disposed on the bottom of the upper plate 1015. According to anexemplary implementation, the number of sub-films constituting the thinfilm TL1 disposed on the top of the upper plate 1015 and the number ofsub-films constituting the thin film TL2 disposed on the bottom of theupper plate 1015 may have the same shape. Specific forms (e.g., widthsor gaps) for a sub-film may have will be described later with referenceto various implementations.

FIG. 14 illustrates an example of an equivalent circuit including aresistance component and an inductor component, where the circuit may bedefined through a thin film included in an induction heating typecooktop and a target heating object.

The induction heating type cooktop 1000 using a thin film TL may form anequivalent circuit including a resistance component and an inductorcomponent when a working coil WC operates in response to placement of atarget heating object HO on the upper plate 1015. In doing so, at leastone of the target heating object HO and the thin film TL may beinductively heated. For example, referring to FIG. 14 , R_(X) and L_(X)may correspond to a resistance component and an inductor componentassociated with the target heating object HO, and I_(X) may correspondto an induced current induced from the target heating object HO. Inaddition, R_(Y) and L_(Y) may correspond to a resistance component andan inductor component associated with the thin film TL, and I_(Y) maycorrespond to an induced current induced from the thin film TL. However,R_(X), L_(X), R_(Y) and L_(Y) shown in FIG. 14 show an equivalentcircuit formed by the physical configurations (that is, the targetheating object HO and the thin film TL) when the working coil WC isoperated. Thus, R_(X), L_(X), R_(Y) and L_(Y) may be understood asvarious types of a total resistance component and a total inductorcomponent, and the like, and may be illustrated in other forms.Therefore, the correspondence between the resistance component, theinductor component, and the physical configuration described in theabove implementation may be expressed in various forms that can beunderstood by a person skilled in the art in order to indicate acharacteristic that an induced current flows in the target heatingobject HO. In some implementations, R_(Y) and L_(Y) illustrated in FIG.14 may correspond to a total resistance component and a total inductorcomponent of the plurality of sub-films constituting the thin film TL,in which case I_(Y) may correspond to the total sum of the inducedcurrents induced from the plurality of sub-films.

However, FIG. 14 is a diagram for explaining an induction heatingprocess by an induction current of a thin film TL including a pluralityof thin films, and thus, the corresponding characteristic should not belimited to the implementation illustrated in FIG. 14 . That is, when thetarget heating object HO as a nonmagnetic object is disposed on theupper plate 1015, it may be understood that an equivalent circuit asshown in FIG. 7 is formed by a plurality of sub-films.

FIG. 15 illustrates an example of a thin film including a plurality ofsub-films.

In some implementations, a thin film TL may include a plurality ofsub-films capable of being inductively heated, and each sub-film may bespaced apart from each other. In some implementations, the sub-films mayhave a ring shape such that central portions of the sub-films overlapeach other. Here, the central portions may be each defined as a center(e.g., a portion in which at least one of the horizontal length and thevertical length is half) of each of the sub-films having variouspolygonal shapes that can be understood by those skilled in the art.Referring to FIG. 15 , sub-films 1202 a, 1202 b, 1204 a, 1204 b, and1206 b constituting thin films 1200 a and 1200 b are illustrated in acircular ring shape, in which case central portions of the sub-films1202 a, 1202 b, 1204 a, 1204 b, 1206 b may be understood as the centerof the circular ring. However, the shapes of the sub-films 1202 a, 1202b, 1204 a, 1204 b, and 1206 b do not need to be limited tointerpretation as shown in FIG. 15 , and may be understood as variousforms forming a loop with a predetermined area.

Referring to FIG. 15 , the thin film 1200 a may include two sub-films1202 a and 1204 a having a ring shape, and the sub-films 1202 a and 1204a may be spaced apart from each other. Since the sub-films 1202 a and1204 a are in a ring shape with a central portion punctured,predetermined components (e.g., a temperature sensor such as athermistor) included in the cooktop 1000 may be disposed. In addition,since a gap exists between the sub-films 1202 a and 1204 a, atemperature sensor such as a thermocouple may be disposed in the gap.

Referring to FIG. 15 , the thin film 1200 b may include a plurality ofsub-films 1202 b, 1204 b, and 1206 b, and the sub-film 1202 b disposedin the center among these is in a ring shape with a central portionwhich is not punctured. That is, the thin film 1200 b may include aplurality of the sub-film 1202 b, 1204 b, and 1206 b, including thesub-film 1202 b having a central portion not punctured. In someimplementations, a gap exists between the sub-films 1202 a and 1204 a,and a temperature sensor such as a thermocouple may be disposed in thegap.

FIG. 16A illustrates an example a thin film including a plurality ofsub-films that are disposed on a top and a bottom of an upper plate.

In some implementations, a thin film TL may include a plurality ofsub-films STL1 and STL2 that may be inductively heated, and the thinfilm TL may be disposed on the top and bottom of the upper plate 1015.In some examples, where the thin film TL includes two sub-films STL1 andSTL2, the sub-films STL1 and STL2 may be respectively disposed on thetop and bottom of the upper plate 1015 to be inductively heated.

FIG. 16B illustrates a plan view of the thin film including theplurality of sub-films of FIG. 16A. The plurality of sub-films may bedisposed on the top and the bottom of the upper plate.

Referring to FIG. 16B, the sub-film STL2 outlined by a dotted line isdisposed on the bottom of the upper plate 1015, and the sub-film STL1outlined by a solid line is disposed on the top of the upper plate 1015.According to an exemplary implementation, the plurality of sub-filmsSTL1 and STL2 disposed on the top and the bottom of the upper plate 1015may be arranged so as not to overlap each other when viewed from abovethe upper plate 1015. That is, when viewed from above the upper plate1015, the plurality of sub-films STL1 and STL2 may not overlap eachother, so that gaps may exist between the respective sub-films.

FIG. 17A illustrates an example of a thin film including a plurality ofsub-films that are disposed on a top and a bottom of an upper plate, andFIG. 17B illustrates a plan view of the thin film including theplurality of sub-films of FIG. 17A. The plurality of sub-films may bedisposed on the top and the bottom of the upper plate.

Referring to FIGS. 17A and 17B, in some implementations, a thin film TLmay include a plurality of sub-films STL1 and STL2 capable of beinginductively heated, and the thin film TL may be disposed on the top andthe bottom of the upper plate 1015. According to an exemplaryimplementation, the sub-film STL2 outlined by a dotted line is disposedon the bottom of the upper plate 1015, and the sub-film STL1 outlined bya solid line is disposed on the top of the upper plate 1015. In someimplementations, the plurality of sub-films STL1 and STL2 disposed onthe upper and lower ends of the upper plate 1015 may overlap each otherwhen viewed from above the upper plate 1015, unlike FIGS. 16A and 16B.That is, when viewed from above the upper plate 1015, the plurality ofsub-films STL1 and STL2 may overlap each other, so that portions heatedto a lower temperature than portions heated to the highest temperatureoverlap each other, thereby preventing temperature decrease in a gapbetween the sub-films STL1 and STL2 on the plan view. In someimplementations, the sub-films STL1 and STL2 overlap each other on theplan view, but the sub-films STL1 and STL2 do not contact each other dueto the upper plate 1015 and other components on a side view, and thus,the sub-films STL1 and STL2 have a gap to be spaced apart from eachother.

FIGS. 16A, 16B, 17A, and 17B are views for explaining variousarrangement methods of the thin film TL including the plurality ofsub-films STL1 and STL2, and thus, the present disclosure need not belimited to the illustrated implementations. That is, the number of theplurality of sub-films STL1 and STL2 constituting the thin film TL maybe two or more, and may be disposed at least one of the upper end andthe lower end of the upper plate 1015. This arrangement may also beunderstood as a manner in which each of the sub-films STL1 and STL2described through the above various implementations are spaced apartfrom each other

In some implementations, the thin film TL may include a plurality ofsub-films having a predetermined shape. In some implementations, theplurality of sub-films constituting the thin film TL may have at leastone type of width. In some examples, a width in each of the plurality ofsub-films may or may not be uniform.

In some implementations, a thickness of each of the plurality ofsub-films STL1 and STL2 may be thinner than a skin depth of theplurality of sub-films STL1 and STL2.

In some implementations, when the plurality of sub-films STL1 and STL2overlap, the sum of the thicknesses of the plurality of sub-films STL1and STL2 in the overlapped portion may be thinner than the skin depth.

FIG. 18 illustrates various types of width allowed for a plurality ofsub-films constituting a thin film.

Referring to FIG. 18 , a thin film TL included in the induction heatingtype cooktop 1000 may include a thin film 1800 a including sub-films1802 a and 1804 a having a predetermined single width 1803 a and 1805 a,a thin film 1800 b including sub-films 1802 b and 1804 b having aplurality of types of widths 1803 b and 1805 b, or a thin film 1800 cincluding sub-films 1802 c and 1804 c having a non-uniform width 1801 cand 1803 c.

In some implementations, a criterion of whether the thin film TL to beused in the induction heating type cooktop 1000 has the predeterminedsingle width 1803 a and 1805 a or the plurality of types of widths 1803b and 1805 b may be based on a point which is inductively heated by eachworking coil WC. That is, it may be determined as to whether a sub-filminductively heated by each working coil WC has the predetermined singlewidth 1803 a and 1805 a or the plurality of types of widths 1803 b and1805 b.

In some examples, each of the sub-films 1802 a and 1804 a may have oneor more widths defined along the upper plate.

In some implementations, whether the thin film TL has the predeterminedsingle width 1803 a or 1805 a or the plurality of types of widths 1803 band 1805 b may be determined for each of the top and the bottom of theupper plate 1015 of the induction heating type cooktop 1000. In someimplementations, the plurality of sub-films may be disposed on at leastone of the top and bottom of the upper plate 1015, and when theplurality of sub-films are disposed on the top or bottom portion of theupper plate 1015, the plurality of sub-films may have an upper portion.Alternatively, each of the lower ends may have a predetermined singlewidth 1803 a and 1805 a or a plurality of types of widths 1803 b and1805 b.

In some implementations, a plurality of sub-films may be disposed onboth the top and the bottom of the upper plate 1015. In this case, theplurality of sub-films may have the predetermined single width 1803 aand 1805 a or the plurality of types of width 1803 b and 1805 b on boththe top and the bottom of the upper plate 1015. For example, a pluralityof sub-films disposed on the top of the upper plate 1015 may have asingle width, and a plurality of sub-films disposed on the bottom of theupper plate 1015 may have a single width. In this case, a width of aplurality of sub-films may be different depending on whether theplurality of sub-films is disposed on the top or the bottom of the upperplate 1015.

In some implementations, at least one of the plurality of sub-films 1802c and 1804 c constituting the thin film 1800 c may have a non-uniformwidth. For example, one of the plurality of sub-films 1802 cconstituting the thin film 1800 c may have a non-uniform width within arange from the first width 1801 c to the second width 1803 c.

FIG. 19 illustrates examples of various types of a plurality ofsub-films of a thin film and example gaps defined between the pluralityof sub-films.

Referring to FIG. 19 , a thin film 1900 a may include a plurality ofsub-films 1901 a, 1903 a, and 1905 a, and the plurality of thin films1901 a, 1903 a, and 1905 a may be spaced apart with gaps 1902 a and 1904a therebetween. In some implementations, the gaps 1902 a and 1904 abetween the plurality of thin films 1901 a, 1903 a, and 1905 a may beuniform and may have a plurality of distances.

In some implementations, a thin film 1900 b may include a plurality ofsub-films 1901 b, 1903 b, and 1905 b. Among the plurality of sub-films1901 b, 1903 b, and 1905 b, some sub-films 1901 b and 1903 b may bespaced apart from each other with a gap that is non-uniform in a rangefrom a first gap 1902 b to the second gap 1904 b. In someimplementations, the thin film 1900 b may be configured such that thesub-films 1901 b and 1903 b have a non-uniform gap while other sub-films1903 b and 1905 b have a uniform gap (e.g., a gap 1906).

FIG. 20 illustrates an example of heat distribution in a thin filmincluding a plurality of sub-films that are inductively heated.

Specifically, as a thin film TL including a plurality of sub-films isinductively heated, the temperature at which the target heating objectHO can be heated may be distributed uniformly at a high temperature atleast in radial direction in a relatively wider range, as compared withthe case of using a single thin film. Accordingly, it may be possible toefficiently and quickly heat the target heating object HO whileminimizing thermal deformation and damage of the thin film TL.

In some implementations, it may be possible to heat both a magneticobject and a nonmagnetic object at a single induction fire hole by usinga thin film capable of being directly inductively heated.

In some implementations, a thin film to be inductively heated includes aplurality of sub-films, thereby reducing a difference in heatingtemperature in a radial direction within each sub-film and accordinglypreventing damage or thermal deformation of the thin film

In some implementations, a thin film to be inductively heated includes aplurality of sub-films, thereby reducing a difference in heatingtemperature in a radial direction within each sub-film and accordinglypreventing damage or thermal deformation of the thin film.

In addition to the aforementioned effects, other specific effects havebeen described above with reference to the foregoing implementations ofthe present disclosure.

The foregoing description of the present disclosure is not limited tothe aforementioned implementations and the accompanying drawings, and itwill be obvious to those skilled in the technical field to which thepresent disclosure pertains that various substitutions, modifications,and changes may be made within the scope without departing from thetechnical spirit of the present disclosure.

What is claimed is:
 1. An induction heating type cooktop, comprising: acover plate coupled to a top of a case, the cover plate comprising anupper plate configured to seat an object to be heated; a working coildisposed inside the case and configured to heat the object; a thin filmhaving a thickness such that a magnetic field generated by the workingcoil is transmitted through the thin film to the object and having aresistance value such that the thin film is heated by the working coil,the thin film comprising a plurality of sub-films that are arrangedabout a central portion of the thin film, wherein an outer boundary ofone of the plurality of sub-films is positioned on a radially differentposition from an outer boundary of another of the plurality of sub-filmsrelative to the central portion of the thin film.
 2. An inductionheating type cooktop, comprising: a cover plate coupled to a top of acase, the cover plate comprising an upper plate configured to seat anobject to be heated; a working coil disposed inside the case andconfigured to heat the object; a thin film disposed on the upper plateand the thin film comprising a plurality of sub-films that are arrangedabout a central portion of the thin film, at least one of the pluralityof sub-films and the object forming a equivalent circuit, wherein one ofthe plurality of sub-films is spaced apart from another of the pluralityof sub-films so as to form a gap each other.